<!DOCTYPE html>
<html>
<head>
<meta charset="utf-8">
<title>CSS 网页布局 - 菜鸟教程(runoob.com)</title>
<meta name="viewport" content="width=device-width, initial-scale=1">
<style>
body {
  margin: 0;
}

/* 头部样式 */
.header {
  background-color: #f1f1f1;
  padding: 20px;
  text-align: center;
}
</style>
</head>
<body>

<div class="header">
  <h1>头部区域</h1>
</div>

</body>
</html>